Zanaflex

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Zanaflex

INDICATIONS

Zanaflex is a central alpha-2-adrenergic agonist
indicated for the management of spasticity. Because of the short duration of
therapeutic effect, treatment with Zanaflex should be reserved for those daily
activities and times when relief of spasticity is most important [see DOSAGE
AND ADMINISTRATION].

DOSAGE AND ADMINISTRATION

Dosing Information

Zanaflex Capsules® or Zanaflex® tablets may be prescribed
with or without food. Once the formulation has been selected and the decision
to take with or without food has been made, this regimen should not be altered.

Food has complex effects on tizanidine pharmacokinetics,
which differ with the different formulations. Zanaflex Capsules and Zanaflex
tablets are bioequivalent to each other under fasting conditions (more than 3
hours after a meal), but not under fed conditions (within 30 minutes of a
meal). These pharmacokinetic differences may result in clinically significant
differences when switching administration of tablet and capsules and when
switching administration between the fed or fasted state. These changes may
result in increased adverse events, or delayed or more rapid onset of activity,
depending upon the nature of the switch. For this reason, the prescriber should
be thoroughly familiar with the changes in kinetics associated with these
different conditions [see CLINICAL PHARMACOLOGY].

The recommended starting dose is 2 mg. Because the effect
of Zanaflex peaks at approximately 1 to 2 hours post-dose and dissipates
between 3 to 6 hours post-dose, treatment can be repeated at 6 to 8 hour
intervals, as needed, to a maximum of three doses in 24 hours.

Dosage can be gradually increased by 2 mg to 4 mg at each
dose, with 1 to 4 days between dosage increases, until a satisfactory reduction
of muscle tone is achieved. The total daily dose should not exceed 36 mg.
Single doses greater than 16 mg have not been studied.

Dosing in Patients with Renal Impairment

Zanaflex should be used with caution in patients with
renal insufficiency (creatinine clearance < 25 mL/min), as clearance is
reduced by more than 50%. In these patients, during titration, the individual
doses should be reduced. If higher doses are required, individual doses rather
than dosing frequency should be increased [see WARNINGS AND PRECAUTIONS].

Dosing in Patients with Hepatic Impairment

Zanaflex should be used with caution in patients with any
hepatic impairment. In these patients, during titration, the individual doses
should be reduced. If higher doses are required, individual doses rather than
dosing frequency should be increased. Monitoring of aminotransferase levels is
recommended for baseline and 1 month after maximum dose is achieved, or if
hepatic injury is suspected. [see Use In Specific Populations]

Drug Discontinuation

If therapy needs to be discontinued, particularly in
patients who have been receiving high doses (20 mg to 36 mg daily) for long
periods (9 weeks or more) or who may be on concomitant treatment with
narcotics, the dose should be decreased slowly (2 mg to 4 mg per day) to
minimize the risk of withdrawal and rebound hypertension, tachycardia, and
hypertonia [see Drug Abuse and Dependence].

Zanaflex® Tablets

Zanaflex® (tizanidine hydrochloride) tablets are
available as 4 mg white, uncoated tablets containing tizanidine hydrochloride
4.58 mg, equivalent to 4 mg tizanidine base. The tablets have a quadrisecting
score on one side and are debossed with “A594” on the other side. Tablets are
provided as follows: bottles of 150 tablets (NDC -10144-594-15).